Microdialysis is used to monitor the interstitial fluid in various body organs with respect to local metabolic changes. It may also be used in blood vessels. Such a microdialysis catheter is known from e.g. U.S. Pat. No. 6,346,090 Liska et al. and U.S. Pat. No. 6,811,542 and U.S. Pat. No. 6,264,627 also in the name of Liska et al.
U.S. Pat. No. 6,811,542 uses a third transport channel in order to speed up the transport of the dialysate (the perfusate as it has passed through the dialysis chamber), which is a problem the present invention seeks to solve. The perfusate from the third channel complicates the tests made on the dialysate as well as the pumping techniques.
The invention also seeks to build a catheter which compared to the one in U.S. Pat. No. 6,346,090 is easier to build.